Fig. 2: Activation of long-lived memory CD8 + T cells by OBP-702 in a PAN02 subcutaneous tumor model.
a–c C57BL/6 mice bearing or not bearing PAN02 subcutaneous tumors were intratumorally treated with OBP-702 (1 × 108 PFU) or PBS once and sacrificed 14 days after treatment (a). Splenocytes collected from the harvested spleen were subjected to flow cytometry for SLECs, MPECs, TEMps, and TCMps. Representative figures of flow cytometry are shown in (b), in which CD3+/CD8+ cells are analyzed in the upper figures, and CD3+/CD8+/CD127+ cells are analyzed in the lower figures. Populations of SLECs, MPECs, TEMps, and TCMps are compared among control, OBP-702 vaccination, tumor inoculation, and OBP-702 treatment to tumor (n = 3–4) (c). d, e C57BL/6 mice bearing PAN02 subcutaneous tumors were intratumorally treated with PBS or OBP-702 (5.0 × 107 PFU) three times in a week and sacrificed 28 days after the initial treatment (d). Tumor volume was monitored after treatment by OBP-702 or PBS (n = 5) (e). f, g PAN02 tumors harvested at 28 days after the initial treatment with OBP-702 were subjected to flow cytometry for CD8+ cells and TRMs. Representative figures of flow cytometry are shown in (f), in which live cells are analyzed in the upper figures, and CD8+/CD45+ cells are analyzed in the lower figures. Populations of CD8+ cells and TRMs are compared between control and OBP-702 (n = 3–5) (g). h, i The spleens harvested 28 days after the initial treatment with OBP-702 were subjected to flow cytometry for TEMs and TCMs. Representative figures of flow cytometry are shown in (h), in which CD3+/CD8+ cells are analyzed. Populations of TEMs and TCMs are compared between control and OBP-702 (n = 5) (i). *P < 0.05, **P < 0.005, ***P < 0.001. SLEC short-lived effector T cell, MPEC memory precursor effector cell, TEMp effector memory precursor cell, TCMp central memory precursor cell, TRM tissue-resident memory T cell, TEM effector memory T cell, TCM central memory T cell, Con control, 702 OBP-702.
